How to set the default font in Zimbra 5.0.18 for curent ant future users

The default font now when composing mail is Times new roman. I want to change this to Verdana. I open COS and change default font setting from Times new roman to Verdana but nothing happens.
I checked few mail accounts and their font settings and they were all set to Arial.

If you read my initial post you would noticed
I opened COS and change default font setting from Times new roman to Verdana but nothing happens.
I checked few mail accounts and their font settings and they were all set to Arial.

Is this some kind of bug, or did all my users choose Arial ?

But this doesn't have any effect. Obviously I need to flush cache which I didn't know and I'm gratefull to Saturdays and fyd to point this out.

1. I changed the setting in the COS (times new roman > verdana)
2. I ran "zmprov fc cos default"
3. I opened Zimbra web mail and checked Font setting under settings > composing and there is still Times new roman font selected. Well this makes me a sad panda